Σ-sigma- is formed.
Ba. 696 joins.
Σ-sigma- play their first live.
Ba. 696 leaves, and 遊憂 joins, as well as Dr. syunjyu.
Gt. Siva and Ba. 遊憂 leave, and Σ-sigma- then go on a slight hiatus.
Σ-sigma- resumes activities, and Ba. 696 rejoins.
Σ-sigma- announces their official disbandment.
Σ-sigma- officially disbands
Σ-sigma- was a visual kei band. They were active from 2006 to 2008 and are now disbanded.